Tag Archives: Netflix UI

JavaScript and the Netflix User Interface


JavaScript and the Netflix User Interface

In the two decades since its introduction, JavaScript has become the de facto official language of the Web. JavaScript trumps every other language when it comes to the number of runtime environments in the wild. Nearly every consumer hardware device on the market today supports the language in some way. While this is done most commonly through the integration of a Web browser application, many devices now also support Web views natively as part of the operating system UI (user interface). Across most platforms (phones, tablets, TVs, and game consoles), the Netflix UI, for example, is written almost entirely in JavaScript.

Despite its humble beginnings as a language intended to be Java’s “silly little brother,”4 JavaScript eventually became a key component in enabling the Web 2.0 evolution. Via the introduction of Ajax, this evolution added an element of dynamism to the Web, creating the concept of a living and social Web that is now taken for granted. Today the language’s influence continues to grow as it makes its way into the server landscape via Node.js. For all of its shortcomings, arguably JavaScript has more than successfully achieved the “write once, run anywhere” that Sun Microsystems often used to tout as one of the benefits of Java.

With increasingly more application logic being shifted to the browser, developers have begun to push the boundaries of what JavaScript was originally intended for. Entire desktop applications are now being rebuilt entirely in JavaScript—the Google Docs office suite is one example. Such large applications require creative solutions to manage the complexity of loading the required JavaScript files and their dependencies. The problem can be compounded when introducing multivariate A/B testing, a concept that is at the core of the Netflix DNA. Multivariate testing introduces a number of problems that JavaScript cannot handle using native constructs, one of which is the focus of this article: managing conditional dependencies. Despite this, engineering ingenuity has enabled Netflix to build highly complex and engaging UIs in a rapid and maintainable fashion.